Fuel cell electrode with catalysts grown in situ on ordered structure microporous layer and method for preparing membrane electrode assembly

Abstract

A fuel cell electrode with catalysts grown in situ on an ordered structure microporous layer and a method for preparing a membrane electrode assembly (MEA) are disclosed. The fuel cell electrode includes an electrode substrate layer, a hydrophobic layer, an ordered structure hydrophilic layer and catalysts. The hydrophobic layer is prepared on the electrode substrate layer. The ordered structure hydrophilic layer is prepared on the hydrophobic layer. The catalysts are uniformly distributed on the ordered structure hydrophilic layer.

What is claimed is: 
     
         1 . A fuel cell electrode with catalysts grown in situ on an ordered structure microporous layer, comprising:
 an electrode substrate layer, a hydrophobic layer, an ordered structure hydrophilic layer and catalysts;   wherein the hydrophobic layer is prepared on the electrode substrate layer; the ordered structure hydrophilic layer is prepared on the hydrophobic layer; and the catalysts are uniformly distributed on the ordered structure hydrophilic layer; and   wherein the catalysts are platinum-based catalysts, and a morphology of the platinum-based catalyst is one of nanowires, nanorods and nano-dendrites.   
     
     
         2 . The fuel cell electrode of  claim 1  with catalysts grown in situ on an ordered structure microporous layer, wherein the platinum-based catalyst is selected from the group consisting of platinum, platinum copper, platinum silver, platinum iridium, platinum ruthenium and platinum rhodium. 
     
     
         3 . The fuel cell electrode of  claim 1  with catalysts grown in situ on an ordered structure microporous layer, wherein the electrode substrate layer is selected from the group consisting of a carbon fiber paper, a carbon fiber woven cloth, a carbon black paper and a carbon felt. 
     
     
         4 . The fuel cell electrode of  claim 1  with catalysts grown in situ on an ordered structure microporous layer, wherein the ordered structure hydrophilic layer is an ordered vertical rod array having a monomer diameter of 0.5-1 μm, a pitch of 1-2 μm, and a length of 7-15 μm. 
     
     
         5 . A membrane electrode assembly (MEA) prepared from the fuel cell electrode of  claim 1  with catalysts grown in situ on an ordered structure microporous layer, wherein the fuel cell electrode with the catalysts grown in situ on an ordered structure microporous layer serves as a cathode, a Pt/C electrode serves as an anode, and a proton exchange membrane is provided therebetween. 
     
     
         6 . The MEA of  claim 5  prepared from the fuel cell electrode with catalysts grown in situ on an ordered structure microporous layer, wherein the proton exchange membrane is a perfluorosulfonic acid membrane. 
     
     
         7 . The MEA of  claim 5  prepared from the fuel cell electrode with catalysts grown in situ on an ordered structure microporous layer, wherein the proton exchange membrane is treated with hydrogen peroxide and sulfuric acid. 
     
     
         8 . The MEA of  claim 5  prepared from the fuel cell electrode with catalysts grown in situ on an ordered structure microporous layer, wherein the platinum-based catalyst is selected from the group consisting of platinum, platinum copper, platinum silver, platinum iridium, platinum ruthenium and platinum rhodium. 
     
     
         9 . The MEA of  claim 5  prepared from the fuel cell electrode with catalysts grown in situ on an ordered structure microporous layer  5 , wherein the electrode substrate layer is selected from the group consisting of a carbon fiber paper, a carbon fiber woven cloth, a carbon black paper and a carbon felt. 
     
     
         10 . The MEA of  claim 5  prepared from the fuel cell electrode with catalysts grown in situ on an ordered structure microporous layer, wherein the ordered structure hydrophilic layer is an ordered vertical rod array having a monomer diameter of 0.5-1 μm, a pitch of 1-2 μm, and a length of 7-15 μm. 
     
     
         11 . A method for preparing a membrane electrode assembly (MEA) from a fuel cell electrode with catalysts grown in situ on an ordered structure microporous layer comprising:
 step 1: an electrode substrate layer is prepared as follows: selecting a carbon paper or a carbon cloth as the electrode substrate layer; washing the electrode substrate layer in a boiling organic solvent to remove surface impurities; soaking the electrode substrate layer in a hydrophobic agent for a period of time; followed by drying, sintering, and performing a hydrophobic treatment;   step 2: a hydrophobic layer is prepared as follows: uniformly dispersing a certain amount of acid-treated carbon powder, a hydrophobic agent and a pore-forming agent in isopropanol, and ultrasonically forming a uniformly dispersed slurry; then uniformly spraying the slurry onto one side of the carbon paper or the carbon cloth prepared in step 1 above, followed by drying and sintering the slurry to prepare the hydrophobic layer;   step 3: an ordered structure hydrophilic layer is prepared as follows: uniformly dispersing a certain amount of acid-treated carbon powder, a hydrophilic agent and a pore-forming agent together in isopropanol, and ultrasonically forming a uniformly dispersed slurry; uniformly spraying the slurry onto surfaces of the hydrophobic layer prepared in step 2 above, and etching the hydrophilic layer by an anodic aluminum oxide (AAO) template to form ordered microporous channels before the hydrophilic layer becomes dry; and then completely etching the AAO template with an acid; followed by washing and drying to prepare a gas diffusion layer (GDL) having an ordered porous double microporous layer;   step 4: platinum-based catalysts are grown in-situ as follows: fixing the GDL obtained in step 3 above at a bottom of a reaction container with the hydrophilic layer facing upwards; sequentially adding platinum or a precursor of platinum and other metals, a reducing agent and a surfactant into the container; letting the reaction container stand at room temperature to enable the platinum-based catalysts to be reduced and grown onto the hydrophilic layer ordered array; and, after the reaction is completed, washing and drying the layer to obtain a platinum-based catalytic layer based on an ordered array microporous layer; uniformly dripping a certain amount of a proton conductor solution on a surface of the catalytic layer; letting it stand at room temperature for a period of time to let the proton conductor become uniformly distributed in the catalytic layer; and then drying it to obtain a gas diffusion electrode (GDE) based on the ordered microporous layer; and   step 5: the MEA is prepared as follows: using the GDE prepared in step 4 above as a cathode, and the conventional Pt/C electrode as an anode, placing a proton exchange membrane therebetween, and hot-pressing the layers together to obtain the MEA with catalysts grown in situ on the ordered structure microporous layer.   
     
     
         12 . The method of  claim 11  for preparing the MEA prepared from the fuel cell electrode with catalysts grown in situ on an ordered structure microporous layer, wherein the proton exchange membrane is a perfluorosulfonic acid membrane. 
     
     
         13 . The method of  claim 11  for preparing the MEA prepared from the fuel cell electrode with catalysts grown in situ on an ordered structure microporous layer, wherein the proton exchange membrane is treated with hydrogen peroxide and sulfuric acid. 
     
     
         14 . The method of  claim 11  for preparing the MEA prepared from the fuel cell electrode with catalysts grown in situ on an ordered structure microporous layer, wherein the platinum-based catalyst is selected from the group consisting of platinum, platinum copper, platinum silver, platinum iridium, platinum ruthenium and platinum rhodium. 
     
     
         15 . The method of  claim 11  for preparing the MEA prepared from the fuel cell electrode with catalysts grown in situ on an ordered structure microporous layer, wherein the electrode substrate layer is selected from the group consisting of a carbon fiber paper, a carbon fiber woven cloth, a carbon black paper and a carbon felt. 
     
     
         16 . The method of  claim 11  for preparing the MEA prepared from the fuel cell electrode with catalysts grown in situ on an ordered structure microporous layer, wherein the ordered structure hydrophilic layer is an ordered vertical rod array having a monomer diameter of 0.5-1 μm, a pitch of 1-2 μm, and a length of 7-15 μm.